According to a motor control apparatus of a background art, as a method of setting a gain or a filter, an integral time constant, a position proportional gain Kp, a torque command filter or the like of a speed control portion is calculated from a proportional gain Kv of the speed control portion and an arbitrary digital value is set and stored as an inner parameter. There is such an apparatus setting a certain index (in this case, one parameter gain) from a method of setting a parameter of a servo amplifier.
For example, a motor control apparatus of Patent Reference 1 includes a proportional integral calculating portion, and includes a speed control portion for controlling an angular speed of a motor, when either of a proportional gain (Kv), an integral time constant (Ti) of the speed control portion is set, a gain setting portion capable of setting other gain such that a relationship indicated by the following Equations (1) and (2), or Equations (3) and (4) is always maintained,2π·Kv·Ti≧Cpi (case of proportional integral control type)  (1)where Cpi is a constant which can be set by the following conditionCpi≧4  (2)2π·Kv·Ti≧Cip (case of integral proportional control type)  (3)where Cip is a constant which can be set under the following conditionCip≧2  (4),
a first compensating portion for carrying out proportional calculation, a second compensating portion for carrying out integral calculation, an inputting portion for adding a torque signal (Tref) of the motor outputted by the speed control portion and an output of the first compensating portion and output of the second compensating portion to be inputted to an equivalent rigid model, and inputting a difference signal constituted by subtracting an output of the equivalent rigid model from a speed signal of the speed control portion to the first compensating portion and the second compensating portion, and a vibration detecting portion defining a proportional gain of the first compensating portion by a product a first gain (ζs) by a second gain (ωs), defining an integral gain of the second compensating portion by square of the second gain, constituting the second gain (ωs) by multiplying the proportional gain (Kv) of the proportional calculating portion of the speed control portion by a previously set band setting coefficient (α), comparing an absolute value of a difference signal between the output of the equivalent rigid model and the predicted speed signal of the speed control portion with a previously set detecting speed level, and capable of detecting large or small thereof. Further, in addition to the speed control portion of the motor control apparatus, the motor control apparatus includes a phase control apparatus and when a proportional gain (Kp) of the position control apparatus and either of a proportional gain (Kv), an integral time constant (Ti) of the speed control portion are set, such that a relationship indicated by Equations (1) and (2) mentioned above, or Equations (3) and (4) and equations (5) and (6) shown below is maintained,Kp·Ti≦Cp (integral proportional control type)  (5)where Cp is a constant which can be set under the following conditionCp≦0.32  (6),a gain setting portion capable of setting other gain. Further, according to a method of setting the gain of the motor control apparatus, when a vibration detecting output is present from the vibration detecting portion, a gain setting portion automatically reduces the proportional gain (Kv) by about 10%, and reduces the proportional gain (Kv) repeatedly until the vibration detecting output is not present.
Further, a control parameter adjusting apparatus of a servo motor in Patent Reference 2 is an apparatus of adjusting a plurality of control parameters used for controlling the servo motor. The apparatus includes a first modifying portion for modifying at least one control parameter in the plurality of control parameters, a calculating portion for calculating a change in the at least one control parameter modified by the modifying portion, and a second modifying portion for modifying control parameters other than the at least one control parameter modified by the first modifying portion in the plurality of control parameters based on the calculated change (refer to, for example, Patent Reference 2). A position proportional gain, a speed proportional gain or the like is set for a gain setting apparatus at inside of a servo amplifier by way of a key input portion, a display portion, a storing portion or the like by communicating the servo amplifier with a computer in this way.
In this way, according to the motor control apparatus of the background arts, there is adopted a constitution of setting the gain or the filter time constant at inside of the motor control apparatus by inputting a numerical value for setting of the parameter or the like by an operating person by constituting an inputting apparatus thereof by a computer or an exclusive operator such that an arbitrary value thereof can be taken as finely as possible in order to determine other gain or filter time constant while maintaining a constant rate thereof with the one gain from the relationship with the one gain.    Patent Reference 1: JP-A-2003-189653 (FIG. 2)    Patent Reference 2: JP-A-06-319284 (FIG. 1, FIG. 2, FIG. 7)